Oklahoma Senate: Mullin Appointment Could Create Ripple Effect
March 5, 2026 · 4:04 PM EST
By Nathan L. Gonzales & Jacob Rubashkin
President Donald Trump’s nomination of GOP Sen. Markwayne Mullin to be the next Secretary of Homeland Security is big news for the president’s cabinet, but it doesn’t likely alter the fight for Oklahoma’s Senate seat — or the majority — all that much.
Unlike the situation in Montana after GOP Sen. Steve Daines dropped out of the race, Oklahoma is likely to be more routine. According to state law, GOP Gov. Kevin Stitt will appoint a replacement, who can serve until the November election but must swear an oath that they will not seek the seat themself.
Because the vacancy will occur in the same year that the seat was already scheduled to appear on the ballot, there will not be a separate special election to fill the seat. According to Oklahoma law, the winner of the regularly scheduled race in the fall will instead take office immediately and fill out the remaining two months of the term, rather than waiting until January to be sworn in with the other senators elected in November.
The candidate filing deadline remains on April 3, with a June 16 primary and a potential August 25 runoff, if no candidate receives a majority of the vote.
Mullin’s appointment and likely confirmation could create a ripple effect if one or more of the five Republican members of the House delegation run in the regular election. Then there would presumably be a scramble for any open House seats left behind.
It’s unlikely that a House member will be appointed by Stitt. That would leave Speaker Mike Johnson without a vote on the Hill until that vacancy is filled with a special election. And given law barring the appointee from running in November, a House member is unlikely to give up their seat if they can’t run for the full term.
Oklahoma is firmly a Republican state. Sooner State voters haven't elected a Democrat to the Senate since David Boren won a third term in 1990. It’s been more than 50 years since Oklahoma voted for a Democrat for president and Trump finished ahead of Kamala Harris by 34 points in 2024. And Republicans have a 28-point Baseline advantage. Inside Elections continues to rate the race as Solid Republican.